Abstract:

Background: White spot lesions (WSLs) on dental enamel have been an ongoing dilemma for orthodontists. Patients with fixed orthodontic appliances (braces) appear to have significantly more WSLs. Past research has explored the treatment of these lesions with various remineralising agents, many of which that have relied on patient compliance. A novel intra-oral releasing device (NIRD) has been developed at the University of Otago, and can be used during active orthodontic treatment to address WSLs, and is patient compliance independent.

Objectives: The first objective was to investigate the effects of casein phosphopeptide - amorphous calcium phosphate in Tooth Mousse® (TM) and 0.05% daily acidulated sodium fluoride mouthrinse (F) on WSLs in patients undergoing orthodontic treatment and patients who had recently completed their treatment. The second objective was to compare the effectiveness of TM applied using NIRDs with conventional F application. The third objective was to explore diagnosis and quantification of white spot lesions by means of light induced laser fluorescence DIAGNOdent® (DD) and digital photographic analysis. The fourth objective was to determine the effects of TM or F treatment on Lactobacilli (LB) counts, enamel tactility, plaque acid production and to consider the effects of diet; oral hygiene; decayed, missing and filled teeth (DMFT); socio-economic status (SES) and frequency of product use.

Methods: Thirty-six participants were recruited, and they were randomly allocated into either TM group (18) or F group (18). They were further divided into those undergoing orthodontic treatment and those that had recently had their appliances removed (braces debonded). TM was applied in NIRDs at each review appointment in the treatment group and in a thermoformed tray in the debonded group. F mouthrinse was used as per manufacturers instructions (Colgate®, FluoroCare 200, 0.05% acidulated phosphate fluoride, equal to 900 ppm fluoride ion, cool mint flavour, USA) in both F groups. Sixteen participants were reviewed for eight weeks and twenty were reviewed for twelve weeks. WSL progression or regression was monitored using colour image analysis of digital photographs. Colour histogram values, size and roundness were measured in all participants. Thirty-five photographs were randomly selected from the photograph data set and assessed using a 4-point visual analogue scale. Nineteen postgraduate students and staff took part in this evaluation. White spot lesions were also quantified with DD. The effect of treatment on Lactobacilli (LB) counts, enamel tactility and plaque acid production was also assessed. Finally, confounders such as diet; oral hygiene; DMFT; SES and frequency of product use were analysed.

Results: All participants completed the study. Seventy percent of participants lived in a fluoridated-water area (0.7 - 1.2 ppm). The majority of these participants had diets that were high in acids and sugars. A mixed effect restricted maximum likelihood (REML) regression model found no significant differences at either 8 or 12 weeks of treatment. There were no statistically significant differences between TM or F treatment; however, trends did demonstrate a small reduction in the means for some colour histogram values of the WSLs after twelve weeks of treatment. There were no differences in colour analysis between participants in active treatment or participants who had recently been debonded. DD and size measurements resulted in similar findings, that there were no significant differences between TM or F treatments. There were mixed responses from the participants towards the NIRDs, overall they were well received. On average they lasted for 2.2 days after insertion. Roundness measurements demonstrated statistical significance after six visits (P = 0.00). Lesions became more irregular after 12 weeks of treatment. There was also statistical difference between TM and F groups (P = 0.04), where the F group had a larger increase in roundness score than the TM group. There were no significant changes in plaque acid production and enamel tactility measurements after 12 weeks of treatment. Plaque scores and LB counts were higher in those participants with fixed appliances than in those without. A reduction in plaque scores at visits 4, 5, and 6 was detected for all participants. LB counts reduced with treatment, but this was not statistically significant. No statistically significant effect on treatment outcome was found related to: diet; oral hygiene; DMFT; SES or frequency of product use.

Conclusions: No statistically significant differences were found with TM or Fused for 8 or 12 weeks on the colour, size or fluorescence of WSLs. There were, however, trends indicating slight improvement over time. The NIRD provided a method that was compliant independent, of delivering potential remineralising agents to cervical white spot lesions and with some improvement, may provide a useful adjunct in the treatment of WSLs. However, the efficacy of the agents and the ability of the NIRD to retain the material need to be investigated further. The results of this study indicate that WSLs do not show quantitative or qualitative improvement over a short duration in response to either fluoride or Tooth Mousse application.